Plier type tool with motion-compelling mechanism



Nov. 17, 1964 G. J. PM 3,157,075

PLIER TYPE TOOL WITH MOTION-COMPELLING MECHANISM Filed Jan. 17, 1962 ATTORNEY 5 j wm, EM

United States Patent Oflice a air/n75 Patented Nov. 17, 1964 This invention relates generally to a motion-compelling means for a tool such as a plier-type tool. More particularly, the invention relates to a motion-compelling pawl and ratchet mechanism for a plier-type tool, such as a crimping tool, and means whereby the position of the ratchet may be adjusted to vary the amount of compelled motion.

In plier-type tools such as those used ferrule onto an uninsulated end of wire to thereby provide a mechanical and an electrical connection, it is desirable to provide the tool with a mechanism to prevent the tool from being opened before the ferrule has been crirnped the required amount. This is particularly desirable on a hand-type tool where the depth of crimp could vary with the judgment of the operator. One such mechanism commonly comprises a fixed ratchet and a awl. (ibtain the proper mechanical and electrical connection, a fixed ratchet and a pawl does not allow for manufacturing tolerances which can cause the depth of crimp to vary from tool to tool. Heretotore, tools have been provided with means for adjusting thet amount of compelled motion to provide flexibility in the tool, but due regard has not been given to the criticality of indent in the opera-tion of known adjustable tools.

Accordingly it is an object of this invention to provide a new and improved tool with a highly accurate motioncompelling mechanism.

Another object of the invention is to provide a tool with a new and improved motion-compelling mechanism which may be adjusted .to obtain a required degree of accuracy.

Still another object of the invention is to provide new and improved means for adjusting the minimal jaw closure of a tool such as a crimping tool.

- A still further object of the invention is to provide new and improved means for accurately setting the minimal for crimping a,

However, since the depth of crimp is critical to,

-or wire may be inserted or turned, if desired, in the ferrule to be crimped while the ferrule is in the tool but before any crimping action takes place.

The invention accordingly comprises the features of construction, combinations of elements, and arrangement of par-ts which will be exemplified in the construction hereinafter set forth, and the scope of the invention will be indicated in the claims.

For a fuller understanding of the invention, reference vis had to the following description taken in connectionwith the accompanying drawing, in which:

FIG. 1 is a side elevational view of the crimping tool constructed in accordance with the invention having the jaws spread apart;

FIG. 2 is a sectional view taken along line 2-2 of FIG. 1; 7

FIG. 3 is a sectional view taken along line 3-3 of FIG. 1 more particularly showing the ratchet adjustment;

jaw closure of a tool such as a crimping tool, and locking the setting so that it may not thereafter be readily changed.

Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification.

Generally speaking, in accordance with this invention, a tool such as a pair of pliers having jaws which close one upon the other, is provided with a ratchet and pawl mechanism which prevents the pliers from being opened, once closure has commenced, until minimum jaw closure is attained. The position of the ratchet is adjustable so that the minimal jaw closure may be varied within certain limits to accurately adjust the tool. The adjustment may not thereafter be changed without the useof special tools. v I The pliei-like tool may be provided with jaws having a conventional parallel action movement or may have, for example, a toggle action which is also conventional. In many instances the jaws need not fully close, that is, bottom on one another, to make a satisfactory crimp.

Once the jaws ofvthe tool commence to close, the motion-' compelling mechanism prevents re opening of the jaws so that an electrical connector of the ferrule type may be gripped and supported solely by the tool, that is, released by the operators hand, and an electrical conductor FIG. 4 is a sectional view taken along line 44 of FIG. 1; and

FIG. 5 is an enlarged partial elevational view of .the crimping tool of PEG. 1 with portions of the handles broken away for the sake of clarity and with the jaws nearing the position of minimal closure.

Referring now to FIG. 1, a pair of handles 11 and 12 are provided intermediate their ends through coaxial pin 13 and screw 13 A. pair of jaws 1d and 15 are disposed in parallel relationship one to the other, handle 11 being pivotally attached to jaw 15 as at 16 and handle 12 being pivotally attached to jaw 14- as at 17. Handles 1i and 12 are substantially U-shaped in cross section as shown in f FIG, 2. A guide pin 18 is secured in handle 11 and ex.- tends between the walls thereof. A. guide pin 19 is secured in handle 12 and extends between the walls thereof. laws 14 and 15 are provided with elongated slots 21 and 22 respectively, which extend longitudinally therealong and are disposed to engage guide pins 18 and 19. It will thus be seen that closure of handles 11 and 1.2, causing them to be pivoted about pin 13 and screw 13 effects closure of jaws 14- and 15. The pivot mounting of the jaws on the handles and cooperation of guide pins 18 and 19 with slots 21 and 22 respectively caused the jaws to be maintained in parallel relationship one to the other as the jaws are closed or opened. As illustrated, jaw 15 is provided with a die opening 23 and jaw 14- is provided with a punch pin 24 which cooperates with die opening 23 to form an indented crimp vwhen the jaws are closed on a ferrule. The crimping jaws are shown for purposes of illustration only, it being understood that any of the well-known jaw configurations may be provided in a tool of this type. A spring 25 is attached between jaw 15 and handle 12 to yieldably maintain the tool in the open position.

A ratchet 27 is pivotally mounted at one end thereof to the screw 13* and is positioned between the'legs of handle 11 as shown in FIG. 3. A bolt 28 having a round head 29 and a cam 3@ adjacent the round head is positioned through the legs of handle 11 with head 29 engaging an outer surface of the handle. Ratchet 27 is mounted on bolt 28 through an aperture 31, cam 3d being located within the aperture. A spacer 32 is mounted on bolt 28 and abuts the inner wall of one of the legs of handle 11 to maintain ratchet 27 adjacent the inner side of the other leg of handle ill. A nut 33 is threaded onto the end of bolt 28 to lock the bolt in any set position. The bolt head and nut are provided with spanner grooves 34 to prevent unlocking of the nut or rotation of the cam without use of a special spanner wrench 35. j

The outward end of ratchet 27 is provided with a series of teeth 36 adapted to be engaged by a pawl 37 pivotally mounted to handle 12 by means of pin 38. A spring 39 is attached between pawl 38 and handle 12 to yieldably maintain the pawl in the desired position, which will hereinafter be explained.

Referring now to FIG. 5, as the handles of the tool are closed, pawl 37 engages one of teeth 36 in ratchet 27 thereby rotating the pawl in a counterclockwise direction. As the tool handles approach each other, the pawl will progressively contact each one of the teeth since deflection of pawl 37 in the counterclockwise direction (FIG. 5) is permitted by spring 39. The teeth of the ratchet 27 may be very fine to permit a highly accurate adjustment of the ratchet. However, once pawl 37 engages the first tooth, the pawl cannot thereafter rotate in the clockwise direction to permit the handles to be opened, since the combined distance of the ratchet and pawl from their respective pivot points to their point of contact exceeds the distance between the pivot points. However, once the handles have been closed to provide minimal jaw closure, pawl 37 will move past engagement with the last tooth in ratchet 27 thereby allowing the pawl to be rotated in the clockwise direction by the tension of spring 39. The handles may thereafter be opened.

It may be desirable to permit adjustment of the minimal closure position which occurs after the pawl engages the last tooth in the ratchet. This adjustment is provided by moving the position of the ratchet with respect to the handle on which it is mounted. Referring again to FIG. 3, by loosening nut 33 by means of spanner wrench 35, the spanner wrench may then be used to rotate bolt 28 by engagement of the spanner wrench in spanner grooves 34 in bolt head 29. Rotation of the bolt results in rotation of cam 34 which is in engagement with aperture 31 in the ratchet. Referring again to FIG. 5, it will be seen that rotation of cam 30 may change the position of the ratchet from the position shown in full lines in that figure to the position shown in phantom. The ratchet may also be adjusted to any intermediate position. Once the desired position is attained, nut 33 may be retightened to secure the ratchet in the selected position. The tool may thereby be accurately adjusted and locked against undesired re-adjustment. In this manner the tool may be set at the factory without concern that the adjustment will be changed in the field. Thus it will be seen in FIG. 5 that when the jaws are in the position shown and the ratchet is adjusted to the full line position, pawl 37 is in engagement with the last tooth on the ratchet thereby requiring further closure of the tool before it will be released to open. However, if the ratchet is adjusted to the position shown in phantom in that figure, then the pawl would already be past engagement with all the teeth on the ratchet when the jaws are in the position shown, thereby allowing the tool to be open. By this means, the amount of minimal closure required before the tool may be opened, may readily be adjusted within limits required by the workpiece placed between the jaws and the dimensional variations in the numerous plier details.

It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efiiciently attained and, since certain changes may be made in the above construction without departing from the spirit and scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

What is claimed is:

1. In a tool of the type having first and second handles pivoted one to the other and first and second jaws, one mounted on each of said handles, the combination comprising a lever member pivoted to the handles through the pivot of the handles, said lever member having ratchet teeth defined thereon along one end thereof and having an aperture defined therethrough intermediate said teeth and the point to which said lever member is pivoted to the handle, a cam within said aperture and rotatably mounted on the first handle, a pawl pivotally mounted on the second handle, a spring attached between said pawl and the second handle to yieldably maintain said pawl in proper pivotal position to engage said teeth as the first and second handles are caused to close upon each other, whereby engagement of said pawl with one of said teeth will prevent opening of the handles until said pawl has traversed every one of said teeth, said cam upon rotation thereof being effective to engage the walls of said lever member defining the aperture and move said lever member about its pivot point to adjust the position of said ratchet, and means cooperating with said cam for locking said cam in any selected rotational position.

2. In a tool of the type having first and second handles pivoted one to the other and first and second jaws, one mounted on each of said handles, the combination comprising a lever member pivoted to the handles through the pivot of the handles, said lever member having ratchet teeth defined thereon along one end thereof and having an aperture defined therethrough intermediate said teeth and the point to which said lever member is pivoted to the handle, a cam within said aperture and rotatably mounted on the first handle, a pawl pivotally mounted on the second handle, and a spring attached between said pawl and the second handle to yieldably maintain said pawl in proper pivotal position to engage said teeth as the first and second handles are caused to close upon each other, whereby engagement of said pawl with one of said teeth will prevent opening of the handles until said pawl has traversed every one of said teeth, said cam upon rotation thereof being effective to engage the walls of said member defining the aperture and move said lever member about its pivot point to adjust the position of said ratchet, and means for locking said cam in any selected rotational position, the distance between the pivot point of said lever member and the cam being substantially greater than the distance between the cam and the end of said lever member defining the ratchet teeth.

3. In a tool of the type having first and second handles pivoted one to the other and first and second jaws, one mounted on each of said handles, the combination comprising a lever member pivoted to the handles through the pivot of the handles, said lever member having ratchet teeth defined thereon along one end thereof and having an aperture defined therethrough intermediate said teeth and the point to which said lever member is pivoted to the handles, a cam Within said aperture and rotatably mounted on the first handle, a pawl pivotally mounted on the second handle and a spring attached between said pawl and the second handle to yieldably maintain said pawl in proper pivotal position to engage said teeth as the first and second handles are caused to close upon each other, whereby engagement of said pawl with one of said teeth will prevent opening of the handles until said pawl has traversed every one of said teeth, said cam upon rotation thereof being effective to engage the walls of said lever member defining the aperture and move said levcr member about its pivot point to adjust the position of said ratchet, and means for locking said cam in any selected rotational position.

References Cited in the file of this patent UNITED STATES PATENTS 104,426 Clark June 21, 1870 1,581,692 Royall Apr. 20, 1926 FOREIGN PATENTS 1,089,834 Germany Sept. 29, 1960 

1. IN A TOOL OF THE TYPE HAVING FIRST AND SECOND HANDLES PIVOTED ONE TO THE OTHER AND FIRST AND SECOND JAWS, ONE MOUNTED ON EACH OF SAID HANDLES, THE COMBINATION COMPRISING A LEVER MEMBER PIVOTED TO THE HANDLES THROUGH THE PIVOT OF THE HANDLES, SAID LEVER MEMBER HAVING RATCHET TEETH DEFINED THEREON ALONG ONE END THEREOF AND HAVING AN APERTURE DEFINED THERETHROUGH INTERMEDIATE SAID TEETH AND THE POINT TO WHICH SAID LEVER MEMBER IS PIVOTED TO THE HANDLE, A CAM WITHIN SAID APERTURE AND ROTATABLY MOUNTED ON THE FIRST HANDLE, A PAWL PIVOTALLY MOUNTED ON THE SECOND HANDLE, A SPRING ATTACHED BETWEEN SAID PAWL AND THE SECOND HANDLE TO YIELDABLY MAINTAIN SAID PAWL IN PROPER PIVOTAL POSITION TO ENGAGE SAID TEETH AS THE FIRST AND SECOND HANDLES ARE CAUSED TO CLOSE UPON EACH OTHER, WHEREBY ENGAGEMENT OF SAID PAWL WITH ONE OF SAID TEETH WILL PREVENT OPENING OF THE HANDLES UNTIL SAID PAWL HAS TRAVERSED EVERY ONE OF SAID TEETH, SAID CAM UPON ROTATION THEREOF BEING EFFECTIVE TO ENGAGE THE WALLS OF SAID LEVER MEMBER DEFINING THE APERTURE AND MOVE SAID LEVER MEMBER ABOUT ITS PIVOT POINT TO ADJUST THE POSITION OF SAID RATCHET, AND MEANS COOPERATING WITH SAID CAM FOR LOCKING SAID CAM IN ANY SELECTED TOTATIONAL POSITION. 